#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define ALPHANUM "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"

void fnPurge (char* input, char* output);
char* fnTest (char* output); //This is going to return "is" or "is not"

int main (void)
{
 //local declarations
  char chInput[100];
  char chClean[100];

  //get input
  printf("This will test a string of up to 100 characters for palindromicity. \n\nEnter string ==> ");
  fgets(chInput, 100, stdin);
  //scanf("%100[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890]",chClean);
  //purge it
  fnPurge (chInput, chClean);
  //printf ("%s\n",chClean); //diagnostics
  //printf ("%s\n%s\n", chClean,chRev); //just kidding

  //test for palindromicity
  printf ("The string %s a palindrome. \n",fnTest (chClean));

  return 0;
}

void fnPurge (char* input, char* output)
{

  int size;
  int outincr;
  int i;
  outincr = 0;
  size = 0;

  size = strlen(input);



   while (*input != '\0')
  {
    size = strspn(input,ALPHANUM);
    input[size] = '\0';
    strncat (output, input, 99 - strlen(output));
    input += size + 1;
  }


  return;
}

char* fnTest (char* output)
{
  char reverse[100];
  int length;
  char temp;
  int i;
  length = strlen(output);

  for (i = 0; i < length; i++)
  {
    output[length - i -1] = toupper(output[length - i -1]);

    reverse[i] = output[length - i - 1];


  }
  reverse[length] = '\0';

  printf("%s %s\n",output, reverse);

  if (0 == strcmp (reverse, output)) //return text for the user
    return "is";
  else
    return "is not";

}